Examining all post-1995 data for all major ions and parameters using both a linear and general additive model.
Are major ions increasing in concentration in a linear manner over time?
Are there certain months in which said increase is linear?
Biweekly sampling frequency
Sampling once a month
Month | Sampling Frequency | Slope | p-value | Significance |
|---|---|---|---|---|
| 1 | bi-monthly | -0.0048 | 0.466Â | N.S. |
| 1 | monthly | -0.0063 | 0.468Â | N.S. |
| 1 | weekly | -0.0083 | 0.0688 | N.S. |
| 2 | bi-monthly | -0.0084 | 0.196Â | N.S. |
| 2 | monthly | -0.0073 | 0.445Â | N.S. |
| 2 | weekly | -0.0051 | 0.268Â | N.S. |
| 3 | bi-monthly | -0.0059 | 0.467Â | N.S. |
| 3 | monthly | -0.0013 | 0.91Â Â | N.S. |
| 3 | weekly | -0.0049 | 0.314Â | N.S. |
| 4 | bi-monthly | -0.0069 | 0.258Â | N.S. |
| 4 | monthly | -0.0029 | 0.72Â Â | N.S. |
| 4 | weekly | -0.0093 | 0.0315 | * |
| 5 | bi-monthly | -0.0195 | 0.0479 | * |
| 5 | monthly | -0.0123 | 0.22Â Â | N.S. |
| 5 | weekly | -0.0248 | 0.0002 | *** |
| 6 | bi-monthly | -0.0166 | 0.0053 | ** |
| 6 | monthly | -0.0176 | 0.0683 | N.S. |
| 6 | weekly | -0.0165 | 0Â Â Â Â Â | *** |
| 7 | bi-monthly | -0.0058 | 0.302Â | N.S. |
| 7 | monthly | -0.0173 | 0.0304 | * |
| 7 | weekly | -0.0089 | 0.0141 | * |
| 8 | bi-monthly | -0.0208 | 0.0066 | ** |
| 8 | monthly | -0.0233 | 0.0427 | * |
| 8 | weekly | -0.0204 | 0Â Â Â Â Â | *** |
| 9 | bi-monthly | -0.0271 | 0.0072 | ** |
| 9 | monthly | -0.0261 | 0.0903 | N.S. |
| 9 | weekly | -0.0247 | 0.0005 | *** |
| 10 | bi-monthly | -0.0265 | 0.0055 | ** |
| 10 | monthly | -0.0289 | 0.0234 | * |
| 10 | weekly | -0.0283 | 0Â Â Â Â Â | *** |
| 11 | bi-monthly | -0.0188 | 0.0257 | * |
| 11 | monthly | -0.0184 | 0.121Â | N.S. |
| 11 | weekly | -0.0215 | 0.0003 | *** |
| 12 | bi-monthly | -0.0215 | 0.0082 | ** |
| 12 | monthly | -0.0183 | 0.0677 | N.S. |
| 12 | weekly | -0.0192 | 0.0004 | *** |
Biweekly sampling frequency
Sampling once a month
Month | Sampling Frequency | Slope | p-value | Significance |
|---|---|---|---|---|
| 1 | bi-monthly | 0.0237 | 0Â Â Â Â Â | *** |
| 1 | monthly | 0.0242 | 0.0002 | *** |
| 1 | weekly | 0.0236 | 0Â Â Â Â Â | *** |
| 2 | bi-monthly | 0.0303 | 0Â Â Â Â Â | *** |
| 2 | monthly | 0.0225 | 0.0032 | ** |
| 2 | weekly | 0.0301 | 0Â Â Â Â Â | *** |
| 3 | bi-monthly | 0.0166 | 0.0168 | * |
| 3 | monthly | 0.0257 | 0.0139 | * |
| 3 | weekly | 0.0174 | 0.0001 | *** |
| 4 | bi-monthly | 0.016Â | 0.0337 | * |
| 4 | monthly | 0.0126 | 0.219Â | N.S. |
| 4 | weekly | 0.013Â | 0.007Â | ** |
| 5 | bi-monthly | 0.0069 | 0.0741 | N.S. |
| 5 | monthly | 0.0094 | 0.172Â | N.S. |
| 5 | weekly | 0.0099 | 0.0022 | ** |
| 6 | bi-monthly | 0.0005 | 0.891Â | N.S. |
| 6 | monthly | 0.0047 | 0.371Â | N.S. |
| 6 | weekly | 0.0009 | 0.701Â | N.S. |
| 7 | bi-monthly | 0.0049 | 0.126Â | N.S. |
| 7 | monthly | 0.0014 | 0.756Â | N.S. |
| 7 | weekly | 0.0041 | 0.0486 | * |
| 8 | bi-monthly | 0.0068 | 0.114Â | N.S. |
| 8 | monthly | 0.0041 | 0.55Â Â | N.S. |
| 8 | weekly | 0.004Â | 0.185Â | N.S. |
| 9 | bi-monthly | 0.0077 | 0.156Â | N.S. |
| 9 | monthly | 0.0045 | 0.524Â | N.S. |
| 9 | weekly | 0.0069 | 0.0651 | N.S. |
| 10 | bi-monthly | 0.0049 | 0.401Â | N.S. |
| 10 | monthly | 0.0078 | 0.279Â | N.S. |
| 10 | weekly | 0.0081 | 0.0346 | * |
| 11 | bi-monthly | 0.0213 | 0Â Â Â Â Â | *** |
| 11 | monthly | 0.0278 | 0.001Â | *** |
| 11 | weekly | 0.0203 | 0Â Â Â Â Â | *** |
| 12 | bi-monthly | 0.0175 | 0.0003 | *** |
| 12 | monthly | 0.0136 | 0.0425 | * |
| 12 | weekly | 0.0177 | 0Â Â Â Â Â | *** |
Biweekly sampling frequency
Sampling once a month
Month | Sampling Frequency | Slope | p-value | Significance |
|---|---|---|---|---|
| 1 | bi-monthly | -0.0063 | 0.582Â | N.S. |
| 1 | monthly | 0.0083 | 0.571Â | N.S. |
| 1 | weekly | -0.0026 | 0.773Â | N.S. |
| 2 | bi-monthly | -0.0068 | 0.663Â | N.S. |
| 2 | monthly | -0.0043 | 0.861Â | N.S. |
| 2 | weekly | 0.0004 | 0.971Â | N.S. |
| 3 | bi-monthly | -0.0033 | 0.878Â | N.S. |
| 3 | monthly | 0.0258 | 0.368Â | N.S. |
| 3 | weekly | 0.0023 | 0.867Â | N.S. |
| 4 | bi-monthly | -0.0133 | 0.464Â | N.S. |
| 4 | monthly | 0.0144 | 0.589Â | N.S. |
| 4 | weekly | -0.0096 | 0.473Â | N.S. |
| 5 | bi-monthly | 0.0069 | 0.575Â | N.S. |
| 5 | monthly | -0.0055 | 0.748Â | N.S. |
| 5 | weekly | 0.0058 | 0.491Â | N.S. |
| 6 | bi-monthly | 0.0062 | 0.461Â | N.S. |
| 6 | monthly | 0.0094 | 0.495Â | N.S. |
| 6 | weekly | 0.0048 | 0.474Â | N.S. |
| 7 | bi-monthly | 0.0004 | 0.955Â | N.S. |
| 7 | monthly | -0.0136 | 0.108Â | N.S. |
| 7 | weekly | -0.0031 | 0.43Â Â | N.S. |
| 8 | bi-monthly | 0.001Â | 0.939Â | N.S. |
| 8 | monthly | -0.0156 | 0.287Â | N.S. |
| 8 | weekly | -0.0008 | 0.902Â | N.S. |
| 9 | bi-monthly | -0.0103 | 0.132Â | N.S. |
| 9 | monthly | 0.0131 | 0.471Â | N.S. |
| 9 | weekly | 0.0024 | 0.745Â | N.S. |
| 10 | bi-monthly | -0.0048 | 0.555Â | N.S. |
| 10 | monthly | -0.0099 | 0.48Â Â | N.S. |
| 10 | weekly | -0.0104 | 0.0569 | N.S. |
| 11 | bi-monthly | -0.007Â | 0.469Â | N.S. |
| 11 | monthly | -0.0118 | 0.261Â | N.S. |
| 11 | weekly | -0.0193 | 0.0075 | ** |
| 12 | bi-monthly | -0.0186 | 0.106Â | N.S. |
| 12 | monthly | -0.0175 | 0.311Â | N.S. |
| 12 | weekly | -0.0154 | 0.03Â Â | * |
Biweekly sampling frequency
Sampling once a month
Month | Sampling Frequency | Slope | p-value | Significance |
|---|---|---|---|---|
| 1 | bi-monthly | 0.0137 | 0.0854 | N.S. |
| 1 | monthly | 0.0136 | 0.224Â | N.S. |
| 1 | weekly | 0.0164 | 0.0045 | ** |
| 2 | bi-monthly | 0.0083 | 0.207Â | N.S. |
| 2 | monthly | 0.0186 | 0.0813 | N.S. |
| 2 | weekly | 0.0121 | 0.0131 | * |
| 3 | bi-monthly | 0.039Â | 0.0454 | * |
| 3 | monthly | 0.0293 | 0.325Â | N.S. |
| 3 | weekly | 0.0328 | 0.0021 | ** |
| 4 | bi-monthly | 0.0364 | 0.162Â | N.S. |
| 4 | monthly | 0.0596 | 0.0397 | * |
| 4 | weekly | 0.0519 | 0.0024 | ** |
| 5 | bi-monthly | 0.0481 | 0.296Â | N.S. |
| 5 | monthly | 0.0062 | 0.932Â | N.S. |
| 5 | weekly | 0.0098 | 0.754Â | N.S. |
| 6 | bi-monthly | -0.0288 | 0.559Â | N.S. |
| 6 | monthly | -0.0179 | 0.774Â | N.S. |
| 6 | weekly | -0.0055 | 0.865Â | N.S. |
| 7 | bi-monthly | 0.0066 | 0.87Â Â | N.S. |
| 7 | monthly | 0.0807 | 0.164Â | N.S. |
| 7 | weekly | 0.0283 | 0.275Â | N.S. |
| 8 | bi-monthly | 0.0484 | 0.145Â | N.S. |
| 8 | monthly | 0.06Â Â | 0.192Â | N.S. |
| 8 | weekly | 0.05Â Â | 0.0202 | * |
| 9 | bi-monthly | 0.0293 | 0.491Â | N.S. |
| 9 | monthly | 0.09Â Â | 0.217Â | N.S. |
| 9 | weekly | 0.0266 | 0.437Â | N.S. |
| 10 | bi-monthly | -0.0068 | 0.868Â | N.S. |
| 10 | monthly | -0.033Â | 0.573Â | N.S. |
| 10 | weekly | -0.0043 | 0.885Â | N.S. |
| 11 | bi-monthly | 0.0279 | 0.117Â | N.S. |
| 11 | monthly | 0.0353 | 0.215Â | N.S. |
| 11 | weekly | 0.0306 | 0.0078 | ** |
| 12 | bi-monthly | 0.0129 | 0.123Â | N.S. |
| 12 | monthly | 0.0133 | 0.31Â Â | N.S. |
| 12 | weekly | 0.0067 | 0.224Â | N.S. |
Biweekly sampling frequency
Sampling once a month
Biweekly sampling frequency
Sampling once a month
Biweekly sampling frequency
Sampling once a month
Biweekly sampling frequency